This one could be either a 2D sidescroller or an overhead Zelda-style game.

You play as Illios, a forest elf shota who has been in preparations for his coming of age ceremony which requires he go into the woods for ritual meditation and purification. Forest Elf life revolves around sacred jeweled amulets that are center to each life change. You keep the same amulet all your life, until you marry, at which point you and your spouse swap amulets. That means the only person who should touch your amulet besides yourself is the one you wed.

During his forays in the woods, Illios encounters a human girl and the two form a bond, not quite love, but certainly a strong friendship. They agree to meet at the same place every night after his purifications and the two become close. One night, Illios does not find the girl, but instead a Dark Elf woman (potentially milf) who seduces Illios and fucks him ragged until he passes out from the exertion. In the morning, he wakes up to find all his equipment missing, including his amulet. Realizing this means whoever has it can, at any time, declare him their spouse, he sets out to get it back, careful not to let on its significance, lest someone else seize it.

This is where things get complicated.

Forest Elves structure everything around the seasons, and all coming of age ceremonies happen during the start of the Spring mating season, when life returns in strength to the land. All are under Nature's effect to varying degrees, and the Dark Milf left him no clothing.

Level 1: The Forest
The alluring stench of pheromones permeates the air as all seek mates. Beastmen prowl the forest, all searching someone to satisfy their urges.
Enemies:
Bunny Boy: Anthro bunny shotas who just want a hole. Able to gangbang.
Buck: The great Princes of the forest in search of princesses. Forest Elves look feminine enough.
Panthress: A savage ambush predator in the raging heat. Strikes quick and without protection
Momma Bear: Able to take a lot of punishment but does realize non-bears can't survive the loving she gives.

BOSS: The Oester Bunny
The embodiment of Nature and Spring, the spirit of fertility oversees all mating and "helps" any who may be left out this year.

Level 2: The Canyon
The canyon is home to many brutal species who are too happy to enslave any not from around there. Multiple tribes often war for dominance.
Enemies:
Kobold: Slavers who need to make sure the hardware works before it goes to market. They are ranged trappers.
Gnoll: Brutal brawlers.
Gnoll Chieftess: Spell caster.
Kobold Shamaness: Spell caster with a focus on slowing and poisoning.

BOSS: The Ogress
She's in heat. You are tiny. You want to run.

Level 3: Dark Castle
The home of the Dark Elves. Either Illios succeeds here or he becomes just another slave to their dark lusts.
Enemies:
Huntress: Dark Elf girls who need to bag a slave for their own coming of age ceremonies. Uses range.
Elf Boys: Sadistic Dark Elf shotas who love bending any invaders over and degrading them.
Elf Priestess: Conductors of the profane orgies that drive the energies for their dark rituals.

BOSS: The Matriarch
The religious leader of the Dark Elves who does not tolerate intruders. Area of Effect spells are her specialty.

Level 4: The Outlands
As luck would have it, the Dark Elf who stole the amulet was the daughter of the Matriarch who was abducted by orcs not long before Illios arrived. Illios sets out to the orc camp only to be captured himself and given as a courtship present to the wife of the clan Warboss, the Warbitch. When he is given, Illios sees his amulet between the breasts of the Warbitch's daughter. She leaves to go hunting and select her own mate. Illios breaks free and must fight his way out of the camp, freeing the Dark Elf along the way.
Enemies:
Runts: Orc shotas and lolis. Everything in Orc culture is built around power, strength, and fighting. These youth start learning early.
Warriors: Equal numbers male and female, these fighters lead by example.
Shamanz: Holy people of the orcs. They specialize in transformation magic and a type of hypnosis.

BOSSES: The War Couple
The Warboss and Warbitch fight against Illios together and always swap between ranged and melee, each being whatever the other isn't.

Level 5: The Chaos Temple
After freeing the Dark Elf, she informs Illios she sold the human girl to someone she suspected of being a Chaos cultist and that she knows of where their temple might be. Along the way, they find the hunting party from the Orc camp, sans the Boss' daughter. Recognizing the totems received from the Warboss and Warbitch, the hunters help and say cultists and demons abducted the daughter. The group goes to the temple to stop whatever ritual they are planning.
Enemies:
Cultists: Through dark magic, they have all become hermaphrodites. They seek the release of sexual energy to fuel their rites.
Succubus: These demons of lust seduce and entice mortals. 1 in 5 will be a futanari.
Imps: Succubi in training, these little demons flit about and strike quickly. 1 in 5 are traps
Demoness: A succubus without her disguise. These monstrous but elegant creatures leap and dance in their pursuit of souls.

Boss 1: The High Priestess
Illios finds the human girl on the altar as some sort of sacrifice. He intervenes and is halted by the high priestess, who is wearing the amulet. She loves status ailments and area denial.

BOSS 2: The Graven Idol
The image of a forgotten god given unnatural life after Illios refuses to leave, even after getting his amulet back.

BOSS 3: The Stalker of Dreams and Desires
The fell deity is awakened, held in this realm by the jewel in its crown, which contains the human girl. Break the gem, free the girl, banish the deity, and avoid those tentacles.

Following the fight, Illios has his amulet and friend both safely back and heads home for his coming of age ceremony. One problem. After humiliating both the Gnolls and the Kobolds, the two tribes now fight over which tribe Illios now commands, both offering him their fertile females (and a couple males) to try and buy him over.

The daughter of the Orc leaders, having seen Illios fearlessly take on a cult and their deity is now in love with him and will stop at nothing to impress him. Those orc totems from earlier have multiple meanings. One of which is a sign of submission from the Warboss and Warbitch. Beating both of them in combat made both of them his wives (They're orcs, don't try to understand it).

The Dark Elf owes her life and freedom to Illios and has also become enamored with him.